Z-Source DC-DC Converters

When realized as a dc-dc converter, the introduced Z-source impedance network must similarly be short-circuited for a certain defined duty ratio per switching period. The basic operating principles therefore remain unchanged, except that the rear-end converter bridge is changed to one suitable for performing dc-dc conversion. This chapter introduces a few possible dc-dc Z-source topologies for illustration, but will not move deeper into their mathematics since they are almost the same as for dc-ac inversion. This advantage has also been utilized to design multiple converters operating in parallel to achieve a higher power level and premium power quality along with improved system efficiency. The concept of the shoot-through duty cycle to control the output voltage is ruled out completely by simple control of the duty cycle of the switches. Each of the dc-dc converters mentioned above therefore has its unique advantages and disadvantages, which can make them suitable for certain applications but not others.